Electrical Adjustment - Aiwa XR-M88 Service Manual

ELECTRICAL ADJUSTMENT

1
L771
IC771
TP4
R785
< TUNER SECTION >
1. DC Balance/Mono Distortion Adjustment
Settings: • Test point: TP3, TP4
• Adjustment location: L771
• Input level: 60dBµV
Method: Set to FM 98.0MHz and adjust L771 so that
the voltage between TP3 and TP4 becomes
0V±0.04V.
Next, check that the distortion is less than
1.3%.
2. AM IF Adjustment
Settings: • Test point: TP8, TP9
L772 .............................................. 455kHz
3. AM Tracking Adjustment
Settings: • Test point: TP8, TP9
• Adjustment location: L981
Method: Set to AM 603kHz and adjust L981 so that the
test point becomes maximum.
4. AM VT Check
Settings: • Test point: TP1 (VT)
Method: Set to AM 1602kHz and check that the test
point is less than 8.0V.
Then set to AM 531kHz and check that the test
point is more than 0.6V.
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2
L772
30
TP2
TP3
TP1
FFE801
5
L981
GND
TP9 TP8
12 11 10
5. Clock Frequency Check
Settings: • Test point: TP2 (CLK IC771 pin30)
Method: Set to AM 1602kHz and check that the test
point becomes 2052kHz±45Hz.
6. FM VT Check
Settings: • Test point: TP1 (VT)
Method: Set to FM 87.5MHz, 108.0MHz and check that
the test point is more than 0.5V (87.5MHz) and
less than 8.0V (108.0MHz).
21
TUNER C.B
3
CN701